The invention relates to a method and apparatus for melting a fusion adhesive, particularly for edge-gluing machines. In such machines it is known to completely melt a specific amount of fusion adhesive in the form of granules in a melting vessel and to supply the molten fusion adhesive by means of a feed screw or a supply piston to the applicator device for the fusion adhesive. The applicator device can be constructed either as a heatable application roller or as a heatable wedge-shaped nozzle element. Any surplus fusion adhesive which is not applied to the surfaces which are to be bonded, has to be returned again into the melting vessel.
Thus, when starting the edge-gluing machine for the known process, it is first necessary that all of the fusion adhesive which is located in the melting vessel, is melted, whereby a relatively long heating-up time must be taken into account. If the production process requires that the type of fusion adhesive be changed, for example, when a different quality or color of fusion adhesive is required, then a long preparation period is required for changing the types of fusion adhesive in the melting vessel.
A further disadvantage of the known process is seen in the cracking of the fusion adhesive by over-heating, which naturally has a bad effect on the quality of the bond. In addition, gas bubbles and vapor may form in the melting vessel, which is unpleasant for the operator and, under certain circumstances, effects which are detrimental to health may occur.